Physical Constraints in Sensory Ecology
15
log Rate of contact by pheromone
-1.5---~
-1------- -1
0.1
0.2
0.3
0.4
0.5
0.6
0. 7
0.8
0.9
log Relative radius of sperm
Fig. 5. Encounter rates for spenn and pheromone-producing eggs. The contours are the log
of the relative rate. Two peaks are present. At the bottom left, a local peak rate occurs for a
minimum size egg that has no cytoplasm to support pheromone production. At the top left,
very high encounter rates are achieved for small spenn and large eggs producing significant
amounts of pheromone. The location of the valley extending horizontally across the
landscape is influenced by the assumed values for the pheromone parameters. (Data from
Dusenbery 2000)
5 Conclusion
We have seen that for small organisms living free of contact with surfaces or other
constraint on motion, certain processes are relatively easy to evaluate
quantitatively from basic physical principles. These organisms live in the simplest
possible environment, and we have an unusual opportunity to apply physical
principles to aid us in understanding them. This is fortunate, because their world is
quite foreign to us, and our ordinary experience is often misleading. I hope the
success of considering physical constraints in this situation will encourage others
to apply this approach in a wider variety of situations.
15
log Rate of contact by pheromone
-1.5---~
-1------- -1
0.1
0.2
0.3
0.4
0.5
0.6
0. 7
0.8
0.9
log Relative radius of sperm
Fig. 5. Encounter rates for spenn and pheromone-producing eggs. The contours are the log
of the relative rate. Two peaks are present. At the bottom left, a local peak rate occurs for a
minimum size egg that has no cytoplasm to support pheromone production. At the top left,
very high encounter rates are achieved for small spenn and large eggs producing significant
amounts of pheromone. The location of the valley extending horizontally across the
landscape is influenced by the assumed values for the pheromone parameters. (Data from
Dusenbery 2000)
5 Conclusion
We have seen that for small organisms living free of contact with surfaces or other
constraint on motion, certain processes are relatively easy to evaluate
quantitatively from basic physical principles. These organisms live in the simplest
possible environment, and we have an unusual opportunity to apply physical
principles to aid us in understanding them. This is fortunate, because their world is
quite foreign to us, and our ordinary experience is often misleading. I hope the
success of considering physical constraints in this situation will encourage others
to apply this approach in a wider variety of situations.